Process of making boron suboxid.



B WEINTRAUB. RBOOESS OF MAKING BORON SUBOXID. APPLICATION FILED MAY 2, 1913.

1,105,388. Patented July 28, 1914.

Witnesses- Inventor fil Ezechiel Wein'traub flaw. by

His Atformy.

UNITE PATNT FFICE.

EZECHIEL WEINTRAUB, 0F LYNN, MASSACHUSETTS, ASSIG-NCIR TD GENERAL ELECTRIC UGMPANY, A CORPORATION 013 NEW YORK,

PROCESS OF MAKING BORON SUBOXII).

Specification of Letters Patent,

ate1'itetl July 28, 1914.

To all whom it may concern Be it known that I, Ear-Ionian Wnm'rnAUn, acitizen of the United States, residing at Lynn, county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Processes of Making Boron Suboxid, of which the following is a specification.

My present invention comprises a new.

process of producing boron suboxid, a chestnut brown powder commonly referred to as amorphous boron in the chemical literature.

In accordance with my invention, a reaction is produced between a borate, such, for example, as ordinary borax, Na,B,O,, and an oxidizable silicon material, such as elemental silicon, or the monoxid of silicon.

The accompanying drawing illustrates one form of apparatus for carrying out my in- Vent'ion.

In accordance with the preferred form of my process, about seven to eight parts of borax, or other suitable borate, and about one part of silicon are used, although I do not wish to be limited to these particular proportions. The -mate'rial is pulverized, thoroughly mixed, and is then placed in a suitable retort. I I

One form of retort or furnace is shown in the drawing as comprising a refractory container 1, consisting of fire brick or other suitable material, the container preferably being lined with a layer of paper 2 so as to allow an easy separation of the charge 3 from the walls of the container. The furnace is provided with graphite electrodes 4, 5, projecting through the floor of the furnace into contact. with the charge, In order to start the current at a relatively low volt age, a graphite rod 6 may be used to connect the two electrodes. In some cases a core in contact with the electrode and consisting the mixture. In'some cases it is preferable to maintain the temperature somewhat below the boiling point of the charge until near the end of the reaction and then raising it to the boiling point for five to ten minutes before discontinuing the heating. The completion of the reaction usually re quires from one to two hours. After the furnace is cooled, it may be dismantled and the charge, consisting of a brown glassy mass, is crushed.

In order to dissolve uncombined silicon and also prevent the hydrolysis of the sodium, or other alkali silicate, during the pnrification of the charge, I prefer to treat the crushed product with a solution of caustic alkali, such as sodium hydroxid. During the first stages of the purifying process, for example, the crushed metal may be boiled with about ten times its own weight of 25% sodium hydroxid solution. Uncombined silicon is thereby dissolved, and byproducts, such as sodium silicate, washed out. The residue from the treatment is then treated with 1% sodium hydroxid solution and finally with one-half of this volume of a 1 to 2% sodium hydroxid solution until all the free silicon is dissolved, as indicated by the cessation of hydrogen bubbles. Thereupon the washing is continued with water, or by dilute acids, followed with water, until all the soluble impurities have been removed. The same process may be carried out by heating the mixture externally to the reaction temperature in a suitable crucible, such as a Batter-sea crucible. or a Dixon clay-lined crucible, the crucible being preferably lined with several thicknesses of paper. The crucible charge may be heated in a suitable combustion furnace, or electric furnace, such as a resistance furnace, containing a crushed charge of carbon, or similar refractory conductor.

The final product is a brown, insoluble amorphous powder, consisting of boron and oxygen vaporizable without fusion and having the probable formula 13,0. From it elemental boron may be prepared by heating to a very high temperature according to the process described in my Patent No. 1,019,392.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. The process of making boron suboxid which consists in heating a mixture of about- 7 to 8 parts of sodium borate and about one part of silicon to an elevated temperature. to efi'ect a reaction.

2. The process which consists in heating a mixture of about 7 to 8 parts of borax and; about one part of silicon to about the boiling temperature of borax to effect reaction.

3. The process of preparing a sub-oxid of boron which consists in intimately mixing in a pulverized state av borate and an 0x1- dizable silicon material and heating said mixture to the boiling point of making boron suboxid EZEOHIEL \VEINTRAUB.

Witnesses JOHN A. MoMANus, J12, ROBERT SI-IAND. 

